Durability of GFRP Reinforcement Embedded in Concrete


During the last few years, glass fiber reinforced polymer (GFRP) materials have grown gradually in terms of applications, scope, and properties. From automotive and aerospace to oil and civil construction industries, advanced composite materials have gained extraordinary popularity due to their high durability, structural efficiency, fabrication adaptability, and corrosion resistance. Studying the principal constituents of GFRP reinforcement makes it easy to determine the durability of glass fiber-reinforced polymers under different environments.

Major constituents

Major constituents in GFRP materials are the matrix and reinforcing fibers. The matrix functions as the binder for the fibers. There are some other materials such as fillers and coating agents that can be used to enhance or customize the properties of the final product. For instance, the use of coupling agents promotes bonding across the matrix-fiber interface. Similarly, fillers can be utilized to improve the dimensional stability of GFRP bars and reduce their production cost.

As the principal constituent of GFRP reinforcement rebar, fibers occupy the largest volume fraction in a composite laminate. An appropriate selection of fiber volume fraction, fiber type, fiber length, and orientation plays a critical role in defining the characteristics of the final product; Fatigue strength, density, compressive strength and modulus, cost, fatigue failure mechanisms are some of the factors that are directly linked to the selection of the fiber.

Durability of GFRP reinforcement

It is critical to study the microstructural, mechanical, and physical characterization of GFRP rebar subject to a harsh concrete environment in order to further refine these innovative materials. Extensive research has already been carried out to study the performance of composite materials in civil engineering applications. A study was conducted where researchers embedded GFRP rebar in concrete and exposed it to tap water at the temperature up to 50°C to intensify the corrosive power of harsh environment.

The measured tensile strength of the rebar before and after exposure was examined to explore the durability performance of the specimens. Researchers also studied the aging effect on GFRP bars using scanning electron microscopy and differential scanning calorimetry. The results revealed that GFRP reinforcing bars are ideal construction materials for applications where high durability and corrosion-resistance are essential to achieving long service life for concrete structures.

The early application of FRP materials in the civil infrastructures are limited to the repair and retrofit of bridges and buildings. However, extensive research and design codes have been helping structural engineers and the construction industry develop a better understanding of the true potential of FRP composites. It is now globally acknowledged that fiberglass rebar is the best concrete reinforcement materials to fight chloride-induced corrosion.

Considering the fact that one-third of Canada’s 75,000 highway bridges are structurally deficient and have a short remaining service life, it’s high time to develop and implement innovative construction materials, such as fiberglass rebar, in order to slow down the environmental deterioration of concrete and build a sustainable concrete infrastructure.


TUF-BAR is a leading manufacturer and seller of GFRP rebar in North America. We produce fiberglass products using our proprietary patented pultrusion manufacturing process. As a proud member of American Composites Manufacturers Association and the Canada Green Building Council, we only use the highest quality materials to manufacture fiberglass rebar, rock bolts, and form ties. Visit our site to learn more about our products and their properties!